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Collaborating Authors
Results
Redevelopment of a Previously Uneconomic Reservoir from a Mature Oilfield, Offshore South China
Zhenghe, Yan (CNOOC) | Xiaofei, Gao (CNOOC) | Yong, Yang (CNOOC) | Zhihua, Rao (CNOOC) | Donghong, Luo (CNOOC) | Azwar, Olivia (Schlumberger) | Chao, Wang (Schlumberger) | Halomoan, Parlindungan Monris (Schlumberger) | Bisain, Amarjit Singh (Schlumberger)
Abstract After more than 20 years of intensive production in XiJiang oil field, a sand group that consists of multiple reservoirs with a thin oil column of less than 4 m and with strong bottom water drive has been revisited. Some assessments were made previously, including drilling horizontal wells with average recovery factor or only 2.3%. In early 2013, new horizontal well drilling was initiated to reassess these reservoirs with a different approach. The objectives were to optimize the standoff between the lateral and the oil/water contact, which is very critical to well performance, by placing the lateral as close as possible to the reservoir top and to evenly regulate the downhole flow across the draining lateral. The program was successful in reassessing the development reservoirs in the mature oil field that had previously been considered to be uneconomic through a reentry horizontal well drilling program and the implementation of the best practices in operations. The operational practices included the precise landing and lateral placement of horizontal wells and the use of inflow control devices (ICD) for completion. Logging-while-drilling (LWD) bed-boundary mapping, with the ability to map multiple key boundaries, including fluid contact for precise well placement, was integrated with multifunction formation evaluation LWD, which provides real-time formation evaluation to optimize the ICD design for completion. Outstanding outcomes have been observed upon the completion of the well: Producing with 1,600 BOPD with 5% water cut Achieving 56% higher cumulative incremental oil than the best previous horizontal well Exceeding the economic level threshold to develop Comparison of new and the past well performance support the acquisition of the new field data. The successful approach, best practices, and valuable lessons learned provided a breakthrough in developing the previously unexploited reservoir.
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.47)
- Asia > Taiwan > South China Sea > Taiwan Basin (0.99)
- Asia > China > South China Sea > Zhujiangkou Basin (0.99)
- Asia > China > South China Sea > Taiwan Basin (0.99)
- (3 more...)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Drilling > Drilling Measurement, Data Acquisition and Automation > Logging while drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- (2 more...)
Reversing the Production Decline and Maximizing Late-life Value of a Mature Oilfield in Offshore South China โ A Brownfield Re-Development Project Success Story
Luo, Donghong (CNOOC Panyu Operating Co.) | Li, Lin (CNOOC Panyu Operating Co.) | Tao, Bin (CNOOC Panyu Operating Co.) | Halomoan, Parlindungan Monris (Schlumberger) | Bisain, Amarjit Singh (Schlumberger) | Wang, Chao (Schlumberger)
Abstract A brownfield new horizontal wells re-development project was initiated in mid-2012 to arrest the production decline rate of Panyu oilfield with average field water cut of 91% and to further increase its reserve recovery. The new horizontal wells campaign were targeting at the remaining less than 5m thin oil column with strong bottom water drive and the previously unexploited 2m thin layers reserves. However, the re-development and exploiting these targets present operational challenges with increasing complexity. Not only the horizontal well needs to be optimally placed within complex target zone, the lateral also needs to be placed as close as possible to the reservoir top to keep it away from the unknown current fluid contact. This paper features the best practices implemented to optimize the standoff between horizontal section and oil water contact that is very sensitive to well performance and reserve recovery. This includes precise landing with low incident angle and lateral placement within less than 0.5m window below the reservoir top utilizing the directional electromagnetic and wellbore imaging applications for detail reservoir profiles description and current OWC level identification while drilling. Multiple wells' field cases will be discussed in the paper based on 25 horizontal wells completed during the course of the project. Several key outcomes that have been observed during the execution and upon the completion of the well will be highlighted, including:- Clear identification of the reservoir geo-bodies and their interfaces including the current fluid contact level - Optimum lateral placement in the best position to drain the remaining hydrocarbon - Reversing the production decline trend and exceeding the cumulative incremental oil by 45% over the forecast. Finally, the authors conclude that significant oil reserve can remain in mature fields and be recovered through re-entry horizontal wells drilling program. The implementation of the best practices in operation is the key enabler to effectively place the trajectory in the best place to drain the remaining hydrocarbon that lead to maximizing the late-life value of a mature oilfield.
- Asia > China > South China Sea (1.00)
- North America > United States > Texas (0.88)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.69)
- Geology > Structural Geology > Tectonics (0.68)
- Geology > Geological Subdiscipline (0.68)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (0.54)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > Block 30/6 > Veslefrikk Field > Statfjord Group Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > Block 30/6 > Veslefrikk Field > Dunlin Group Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > Block 30/6 > Veslefrikk Field > Brent Group Formation (0.99)
- (9 more...)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring (1.00)
Unlocking the Potential of Complex Marginal Reservoir in Highly Mature Oil Field, XiJiang24 South China Sea
Donghong, Luo (CNOOC) | Zhenghe, Yan (CNOOC) | Xiaofei, Gao (CNOOC) | Zhihua, Rao (CNOOC) | Yu, Du Ding (CNOOC) | Halomoan, Parlindungan Monris (Schlumberger) | Bisain, Amarjit Singh (Schlumberger) | Yang, Liu (Schlumberger) | Azwar, Olivia (Schlumberger)
Abstract An oil & gas operator in XiJiang block offshore South China has shifted the development of highly mature oil fields that have been producing for 17 years toward the remaining undeveloped marginal reservoirs using a horizontal well drilling program. The main targets of the new development campaign are the remaining thin oil column reserve in attic locations of the reservoirs as well as the unproduced thin laminated reservoirs in the area. Upon understanding the uncertainties and challenges associated with drilling horizontal wells in these complex reservoirs, an innovative drilling approach was initiated for accurate horizontal placement in thin sands, channel sands, and thin oil column reservoirs with strong bottom-water. The approach includes the integration of an advance multifunction formation evaluation Logging-While-Drilling (LWD) tool that provides real-time formation evaluation and structural interpretation along with a bed boundary mapper LWD tool with the ability to map multiple key boundaries that are the prerequisite parameters that must be identified during the execution stage and which include the water contact and top and bottom of the reservoir structure simultaneously in distance. Outstanding outcomes have been observed by implementing this new approach in the complex target reservoirs. The approach was applied to multiple challenging wells, each of which has produced from 2,000 to 6,000 BOPD with very low water cut, far exceeding the set production goals of 1,500 to 2,000 BOPD. These are very promising development economics in the oil fields that have 90% to 95% water cut on average. The successful implementation of the new development strategy in highly mature oil fields will lead to sustained and extended production, increasing the ultimate recovery and well economics. The approach provides an example of using integrated technology solutions to overcome the challenges in complex target reservoirs.
- Asia > China > South China Sea (0.70)
- North America > United States > Texas (0.46)
- Geology > Geological Subdiscipline > Stratigraphy (0.68)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.47)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > Block 30/6 > Veslefrikk Field > Statfjord Group Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > Block 30/6 > Veslefrikk Field > Dunlin Group Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > North Viking Graben > Block 30/6 > Veslefrikk Field > Brent Group Formation (0.99)
- (6 more...)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Drilling > Drilling Measurement, Data Acquisition and Automation > Logging while drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- (2 more...)